Liquid fuel atomizer



March 18, 1952 W. J. LINN 2,589,946

LIQUID FUEL ATOMIZER Filed April 1. 1949 2 SHEETS-SHEET 2 '(Ittorneg Patented Mar. 18, 1952 UNITED S TATES PATENT :QFFYICE LIQUID FUEL ATOMIZER William J. Linn, Pittsburgh, Pa.

Application April 1, 1949, Serial No. 84,820

' v V 6 Claims. (Cl. 48- 1'80) Thisinvention relates to liquid fuel atomizers and mixers and particularly-to devices of this type as used in =connectionwith the fuel and air charging ducts in carburetors and manifolds of internal combustion enginesfor improving the degree of mixing and the quality of the explosive mixture delivered to the combustion chamber.

Various devices havebeen suggested for this purpose, none of which,'however completely and successfully atomizes the liquid fuel so as to prevent unatomized' liquid fuel from entering into the combustion chamber of the engine cylinders. Unatomized liquid :fuel, usually in the-form of "small droplets, is extremely undesirable in the combustion chamber since it tends to pass around the piston rings during the compression stroke of the engine and to pass into the crankcase where it dilutes the oil. This produces a reduction in the lubricating qualities of the oil,

thereby increasing friction, causing excessive carbon build up and loss of thermaland mechanical efliciency.

The present invention obviates these difliculties b more efiectively atomizing the liquid fuel 'in the'air and fuel charging duct. This is accomplished bythe use of diffuser means disposed'substantially centrally of the axis of the duct which may take the form of a pin or a plurality of pins projecting inwardly toward the center of the duct on a line'normal to the duct wall and terminating adjacentthe mid-pointer axis of-the duct interior. This diifuser means-obstructs the flow 1of-thefuel and air and creates turbulence which breaksup the fuel droplets and more effectively mixes them with the air. "More effective atomizing and diffusing of the liquid fuel and air maybe accomplished by combining "the diifuser means with a flow velocity changing means,-such as a venturi, for alternately-accelerating and deceleratingthe air and fuel mixture. When used in combination with a -venturi, the diffuser means is preferably placed in the-venturi at a point adjacent the restricting ridge so that the turbulence created by the one is immediately augmentedby the turbulence created by the other, thereby breaking up the fuel droplets and thoroughly mixing them with the air.

The efficiency of this combination results from the considerable turbulence which is created, in the fuel and airstream, first by the flow velocity changing means which may take the form of a single or a plurality of Venturi tubes, and second by the diffuser means which generally includes a pin projecting inwardly from the inthroat,

terior of the flow velocity :changing means toward the center of the duct-on 4 a line -normal $0 the .wall of said duct and terminating adjacent the .duct axis. An air :and .fuel mixture passing through a charging duct in which the combination of this invention is installed is alternately axially and radially accelerated and decelerated by the Venturi action of -.the :fiow changing means. "This .:created peripheral :"turbulence in the mixture, causing :(the particles of fuel to be broken up and I intermingled --:with {the air.

There is, however, insufficient turbulence created at the center of t the stream aof ifuelrand -air-to mix and atomize this center most effectively. The diffuser :means projecting into the center of the ductacts upon-this .centraliportion of the fuel .and :air stream and creates ,a medianturbulencewhichin conjunction :withthe peripheral turbulence createdby the flow changing means causes the fuel to .be :more nearly completely atomized and intermixed with the air than has heretofore Tbeen possible.

Apassage may be inserted .through the diffuser means intermediate its :ends and substantially parallel to :the ductwall, wherebyithe fuel and air=mixture adjacent athe duct-wall is *passed through'the pin. Such a passagezwill create additional turbulence .in the imixture.

The diffuser means may be inserted into opposed :sides of a tubular sleeve having an :outer collecting well 'from'whichopenings'in the sleeve introduce collected raw fuelinto .the interior of the sleeve at points directly above the opposed diffuser :means. The diffuser means and :open- *ings 'fromthe well are spaced about 90 degrees fromtheaxis of a butterfly valve in the carburetor which butterfly valve has a high side :and alow side when :closed. The diffuser pin directly beneath the :high-side .-.of the butterfly valve maybe shorter -.than :the corresponding pin directly 7 beneath the low side of 'the'butterfly valve, thereby creating a more sinuous path Figure is a side elevation of the diffuser means of Figure 4.

Figure 6 is a top plan view of a third embodiment of the difiuser means of this invention.

Figure 7 is a top plan view of the diffuser means of Figure 6.

Figure 8 is a vertical section through an air and fuel charging duct showing another embodiment of the flow charging means and diffuser means of this invention.

Figure 9 is a section on line 9-9 in Figure 1.

Figure 10 is a vertical section through an air and fuel charging duct showing a further embodiment of this invention.

Figure 11 is a vertical section of another embodiment of the invention.

Referring first to Figure 1, there is illustrated a conventional manifold inlet in having a flange ll connected to a flange I2 of the carburetor l3 thereby forming a passage l4 hereafter entitled a Fuel and air charging duct. The butterfly valve l5 of the carburetor is located in the carburetor body between the flange l2 and the fuel jet [6. A gasket I1 is interposed between the "flanges H and I2 to provide airtight sealing between the carburetor and manifold. An idling jet I8 communicates by a passage IS with a fuel chamber (not shown) of the carburetor and furnishes fuel for idling when the butterfly valve 15 is near closing position, as shown. Adjusting screw serves to regulate the free area of idling jet l1 and with it the amount of fuel supplied and the speed of the idling engine.

Such a carburetor manifold combination is generally old and will supply only partially atomized fuel to the engine. A combination of this type is subject to all of the undesirable qualities which have been previously mentioned as characteristic of ordinary carburetors and which are solved by this invention.

A flow velocity changing means is inserted into the air and fuel charging duct M by means of a flange 22 inserted between the inner edges of the carburetor flange l2 and the manifold flange H. The flow velocity changing means includes a radial baflle surface 23 extending peripherally about the interior of the duct. A peripheral well 24 adjoins the baflle surface 23 and lies within the body of the Venturi tube 25. Openings 26 through the wall of the Venturi tube communicate between the well 24 and the interior of the venturi. 'The Venturi tube' has alternate restricting ridges 21 which define pockets 28 within the venturi. These ridges may be sharp and undercut, thereby causing liquid fuel flowing along the Wall to be detached therefrom due to the abrupt change of direction of the inner walls at the ridges and the turbulence in the air stream caused by the abrupt change.

The liquid fuel detached from these ridges is caused to be mixed with the fuel and air mixture by the turbulent movement of the mixture as it passes through the restricting ridges 21 into the enlarged pockets 28.

A diffuser pin 29 projects inwardly into the venturi on a, line normal to the wall of the duct and terminates at a point adjacent the axis of the duct. A passage 30 extends through the pin 20 intermediate its end and parallel to the well of the duct [4. An enlarged tapered opening 31 forms an entrance to the passage 30 and. gives to the passage somewhat the effect of a venturi.

In Figure 8 is shown another embodiment of this invention in which a series of diffuser pins 32 project inwardly from opposite directions in 4 a plurality of separate Venturi tubes 33 of increasing radius mounted in the duct l4.

The difiuser pin 29 is more clearly illustrated in Figures 2 and 3 as a cylindrical body 34 adapted to be inserted into an open-ing 35 in the wall of a venturi. The inwardly projecting end 36 is cut to form a semi-ovoid plane face 3'! which faces the incoming fuel and air mixture. The end 36 terminates in a straight line 38 which acts to create additional turbulence in the fuel and air mixture.

Referring to Figures 4 and 5 there is illustrated a diffuser means having a body portion 39 adapted to be inserted into an opening 35 in the wall of the venturi. A wedge-shaped portion 40 having plane faces 4| and 42 intersecting along a line 43 which forms the apex of the wedge is directed into the stream of air and fuel and acts to divide the stream. The inwardly projecting end 44 of the body portion 39 is cut at an acute angle to the lower side 45 of the body portion thereby forming a sloping plane surface 46 which faces into the stream of air and fuel. A passage 41 having an enlarged tapered opening 48 passes through the body portion 39 in the same manner and for the same purpose as the passage 30 and opening 3| of the diffuser means illustrated in Figures 2 and 3.

In Figures 6 and 7 appears a third embodiment of the diffuser means in which the body portion 49 has the form of a half cylinder having a flat plane surface 50 which is directed into the stream of air and fuel. A passage 5| having an enlarged opening 52 passes through the body portion 49 and serves the same purpose as the corresponding passage in the diffuser means of Figures 2 through 5.

In Figure 10 is illustrated a further embodiment of this invention in which a manifold inlet, carburetor body, and butterfly valve as shown in Figure 1 are combined with a tubular sleeve 60 having a flange 61 inserted between the inner edges of the carburetor flange l2 and manifold flange II. The tubular sleeve 60 includes a radial bafile surface 62 extending peripherally about the interior of the duct. A peripheral well 63 adjoins the baffle surface 62 and lies within the body of the sleeve 60. Opposed openings 64 through the wall of the sleeve communicate between the well 63 and the interior of the sleeve. Each of these openings lies degrees from the axis of the butterfly valve l5, which valve is so positioned in the carburetor that it has a high side 66 and low side 61 when in the closed position. A diffuser pin 65 extends into the interior of the sleeve a distance less than the internal radius of the sleeve from a point directly beneath the opening 64 which lies beneath the high side 66 of the butterfly valve. A second difiuser pin 68 extends into the sleeve a distance greater than the internal radius of the sleeve from a point directly beneath the opening 64 which lies beneath the low side 61 of the butterfly valve. Each of these diffuser pins has an opening 69 therethrough on a, line parallel to a vertical line through the corresponding openings 64 in sleeve 60.

In the embodiment illustrated in Figure 11, the tubular sleeve 60 carries a plurality of diffuser pins 15 which may be of different lengths and which may be located at diiferent points on the wall of the sleeve.

In operation an internal combustion engine having the device of this invention, the liquid fuel is introduced into the air and fuel duct l4 from the jet I6, where it is picked up by a stream of air and carried along the duct. A considerable portion of the fuel remains in the form of large drops which impinge on the wall of the duct. This portion of the fuel is collected in the wells 24 and reintroduced into the fuel and air stream through the openings 26 in the walls of the venturi. The fuel and air mixture which passes along the duct enters the venturi where it is alternately accelerated and decelerated by passing through between the restricting ridges 21 and the enlarged pockets 28. This alternate acceleration and deceleration causes the flow of the fuel and air mixture to become turbulent, especially along the periphery of the stream, thereby intermixing the fuel and air and breaking the fuel into smaller particles.

At engine idling speed the fuel from the well 24 is drawn through openings 26 in wall of the Venturi tube after which part of the mixture passes through passage 30 which extends through pin 29. Upon further opening of the throttle [5 the mixture stream strikes the plane surface 31 from which it is deflected angularly into the fuel and air through the entire central portion of the fuel and air mixture and causes it to become more turbulent.

The turbulent currents caused by the diffuser means and those caused by the flow changing means cooperate with each other, thereby setting up secondary or compounded turbulence in'the interior of the venturi and the duct. Such in creased turbulence acts to atomize the fuel and intermix the fuel and air to an extent heretofore impossible to attain.

Although several presently preferred embodiments of this invention have been illustrated, it is to be understood that it may be otherwise embodied within the scope of the following claims.

I claim:

1. A liquid fuel atomizer for a fuel and air charging duct of an internal combustion engine comprising a tubular sleeve adapted to be disposed in the duct between the carburetor and the engine and at least one diffuser pin projecting inwardly from the interior of the tubular sleeve toward the center of the duct and. terminating adjacent the axis of said duct, said pin having a. passage therethrough intermediate its ends and substantially parallel to the duct wall whereby the fuel and air mixture adjacent the sleeve wall is directed through the pin with the creation of additional turbulence.

2. A liquid fuel atomizer for a fuel and air charging duct of an internal combustion engine as claimed in claim 1 in which the diffuser pin is a cylindrical pin of substantially less diameter than the internal diameter of the sleeve and having at least one plane surface against which the incoming stream of fuel and air impinges and a passage through the pin adjacent the internal wall of the sleeve and substantially parallel to the duct wall whereby the fuel and air mixture pin with the creation of additional turbulence.

3. A liquid fuel atomizer for a fuel and air charging duct as claimed in claim 1 in which the diffuser pin is a cylindrical pin having a diameter less than one sixth the internal diameter of the sleeve.

4. A liquid fuel atomizer for a fuel and air charging duct of an internal combustion engine comprising a. tubular sleeve adapted to be disposed in the duct between the carbureter and the engine, a restricting ridge formed on the internal wall of the sleeve intermediate its ends and extending circumferentially therearound and forming with the interior of the sleeve a Venturi passage and at least one diffuser pin projecting radially inwardly from a point on the internal wall of the sleeve adjacent the restricted portion and toward the center of the duct and-terminating adjacent the axis of said duct, said pin having a passage therethrough intermediate its ends and substantially parallel to the duct wall whereby the fuel and air mixture adjacent the internal Wall of the sleeve is directed through the pin with the creation of additional turbulence.

5. A liquid fuel atomizer for a fuel and air charging duct of an internal combustion engine as claimed in claim 4 in which the diffuser pin is a cylindrical pin of substantially less diameter than the internal diameter of the sleeve and having at least one plane surface against which the incoming stream of fuel and air impinges and a passage through the pin adjacent the internal wall of the sleeve and substantially parallel to the duct wall whereby the fuel and air mixture adjacent the wall of the sleeve is directed through the pin with the creation of additional turbulence.

6. A liquid fuel atomizer as claimed in claim 5 in which the diffuser pin is a cylindrical pin having a semi-ovoid plane face at the end removed from the sleeve wall formed by cutting through the cylinder at an acute angle to its elements. said plane face being so placed as to be impinged upon by the stream of fuel and air, and an opening through the pin adjacent the internal wall of the sleeve.

WILLIAM J. LINN.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 1,720,246 Smith July 9 1929 1,730,453 Devon Oct. 8, 1929 1,902,275 Borgeson Mar. 21, 1933 1,979,757 Melot Nov. 6, 1934 2,133,623 Linn Oct. 18, 1938 2,191,218 Linn .l Feb. 20, 1940 2,377,088 Linn May 29, 1945 

